Conventionally, optical networks are deployed in static configurations, such as submarine optical networks as well as terrestrial optical networks. With a drive towards scalable, agile and dynamic networking solutions, directionless, contentionless, and gridless (CDCG) Reconfigurable Optical Add/Drop Multiplexers (ROADMs) are required for complete flexibility in wavelength connectivity. A CDCG-ROADM can be programmed to switch connections operating at any wavelength with any spectral requirement to any outgoing direction without contention. This ensures resource optimization in the optical layer. Disadvantageously, CDCG-ROADMs require a large number of optical components with high cost and higher power consumption. In addition, the ROADMs that are deployed in terrestrial applications are not qualified to be deployed at the Branching Units (BUs) in submarine networks. In conventional submarine networks (i.e., undersea or underwater networks), fixed BUs connect branches with the trunk under the ocean. This employs a fixed, pre-determined wavelength arrangement, which limits the flexibility of the network. Reconfigurable BUs (RBUs) based on passive multiplexer/demultiplexer, wavelength blocker (WB), or wavelength selective switch (WSS) technologies have been proposed recently. The RBUs require a large number of switches, and the introduction of WSSs in the BU increases control complexity. In addition, since the RBUs contain additional filtering components, they need some additional amplifiers for insertion loss compensation, and it might be necessary to monitor and equalize the power coming from each branch. Submarine ROADMs using passive branching units such as optical interleavers and de-interleavers have also been proposed. This has limited reconfiguration capability as odd/even channels are separated and sent to the two output ports. Thus, in such a situation, a reconfiguration of the wavelength may be needed from the edge nodes in order to adapt to the traffic change and ensure resource optimization.